Zimbra:

When using NotifyLink for Zimbra, I receive multiple meeting invitations for one single appointment.

If multiple folders are selected to process for a user's account, they will receive one Accept/Decline message for each folder selected. In addition to this there is also one email alert that is sent to the phone for the invitation.

This means that if a user is syncing 5 folders to his device he will receive 5 Accept/Decline messages on his device plus one email notification of this appointment.